Today's corporate IT professionals typically face many challenges to handle the ever increasing information and data. To handle large amount of data, many organizations expand their storage capacity by employing manage storage systems locally in order to maintaining their normal business operating. A conventional approach is to use IP based network attached storage (“NAS”), which effectively provides data storage and services for end users. Moreover, at the enterprise level, the majority storage systems are directly attached or connected to server(s) or host(s) as shown in FIG. 7. These server(s) and/or host(s) are typically used as raw block data devices through conventional communication connection media, such as traditional IDE, SCSI, Fibre Channel, or Ethernet.
The server, which is directly attached to a storage system as illustrated in FIG. 7 typically has many drawbacks, which are described as following:
a) a typical conventional storage management system is only capable of handling 4 TB (terabytes) of data, which is usually not good enough for a typical enterprise storage management system;
b) The most of servers, which are directly attached to storage systems, have problems for further expanding their storage capacity. For example, it may require to purchase new servers in order to increase storage capacity;
c) The storage being attached to a server can only be accessed by the attached server and can not be shared by other servers even if server's storage availability is not evenly distributed across all servers within a organization;
d) Each attached storage system has to be managed separately and this is a nightmare for IT professionals;
e) With the attached storage system, the backup/restore has to go through the data network, this will tax or reduce the network performance;
f) a typical SCSI connection only allows a 12-meter distance for data accessing with 15 storage devices. Similarly, Fibre Channel is limited to 10 kilometers communication distance. Distance limitation effectively prevents them from being the best choice for disaster recovery of the storage system; and
g) The Fibre Channel based storage system cannot handle well for the interoperability. Also, Fibre Channel based storage system is expensive to build and to maintain.
FIG. 8 shows a conventional type of virtual SAN, which is in-band controlled and accessed with which the data path from hosts (1 of FIG. 8) to the SAN units (4 of FIG. 8) going through virtual SAN control management station (2 of FIG. 8). It is not efficient in term of accessing the data by the hosts because the virtual SAN control management station can easily be a performance bottleneck. Similarly, the scalability of this type of virtual SAN is poor.